Gate valves have evolved over the years in several forms including a basic form wherein a drive shaft, projecting into an interior chamber of a valve casing and mounted for rotation about its axis has fixed thereto, a radially projecting arm and wherein, by a ball and socket (orthagonal) mount, a circular valve disk, carried by the arm, is placed in surface contact with the valve casing so as to overlay a circular outlet port. Rotation of the shaft causes the arm to swing and thus move the disk to the side to permit fluid flow from an inlet port in the valve casing, through the chamber carrying the arm and valve disk, to exit through the outlet port. The inlet and outlet ports may be located coaxially on opposite sides of the housing. Further, typically the controlled flow is permitted to fill the chamber and to provide a force on the opposite side of the valve disk tending to maintain the valve disk sealed on the valve seat surrounding the outlet port, during valve closure. Representative U.S. patents directed to such gate valves are U.S. Pat. Nos. 10,557; 1,991,006; 2,443,929 and 2,991,794.
Problems have been experienced particularly where the controlled flow includes particulate matter capable of clogging the chamber, thereby preventing the valve disk from seating adequately when overlying the outlet port and shift to normal, valve closed position. Further, the placement of the inlet port relative to the shaft mounting the arm or the other rotatable components of the valve, creates a problem when the forces developed by the flow of fluid controlled by the gate valve, impinges against these operating components. Bending forces may develop, under certain conditions, on the arm remote from the pivot axis as defined by the drive shaft.
It is therefore a primary object of the present invention to provide an improved gate valve in which the force of the flow entering the chamber housing, is dissipated without deflection of the radial arm or misalignment of the valve disk carried thereby relative to the outlet port, wherein the valve chamber carrying the gate valve disk is purged by the incoming flow during the valve opening or closing and wherein, the incoming flow of fluid through the inlet port is deflected radially of the drive shaft arm into the chamber without bending movements being applied to the shaft, or to the arm fixed to shaft and supporting the valve disk at its outboard end.